xref: /openbmc/linux/drivers/clk/x86/clk-pmc-atom.c (revision 174cd4b1) 
1 /*
2  * Intel Atom platform clocks driver for BayTrail and CherryTrail SoCs
3  *
4  * Copyright (C) 2016, Intel Corporation
5  * Author: Irina Tirdea <irina.tirdea@intel.com>
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms and conditions of the GNU General Public License,
9  * version 2, as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  */
16 
17 #include <linux/clk-provider.h>
18 #include <linux/clkdev.h>
19 #include <linux/err.h>
20 #include <linux/platform_data/x86/clk-pmc-atom.h>
21 #include <linux/platform_device.h>
22 #include <linux/slab.h>
23 
24 #define PLT_CLK_NAME_BASE	"pmc_plt_clk"
25 
26 #define PMC_CLK_CTL_OFFSET		0x60
27 #define PMC_CLK_CTL_SIZE		4
28 #define PMC_CLK_NUM			6
29 #define PMC_CLK_CTL_GATED_ON_D3		0x0
30 #define PMC_CLK_CTL_FORCE_ON		0x1
31 #define PMC_CLK_CTL_FORCE_OFF		0x2
32 #define PMC_CLK_CTL_RESERVED		0x3
33 #define PMC_MASK_CLK_CTL		GENMASK(1, 0)
34 #define PMC_MASK_CLK_FREQ		BIT(2)
35 #define PMC_CLK_FREQ_XTAL		(0 << 2)	/* 25 MHz */
36 #define PMC_CLK_FREQ_PLL		(1 << 2)	/* 19.2 MHz */
37 
38 struct clk_plt_fixed {
39 	struct clk_hw *clk;
40 	struct clk_lookup *lookup;
41 };
42 
43 struct clk_plt {
44 	struct clk_hw hw;
45 	void __iomem *reg;
46 	struct clk_lookup *lookup;
47 	/* protect access to PMC registers */
48 	spinlock_t lock;
49 };
50 
51 #define to_clk_plt(_hw) container_of(_hw, struct clk_plt, hw)
52 
53 struct clk_plt_data {
54 	struct clk_plt_fixed **parents;
55 	u8 nparents;
56 	struct clk_plt *clks[PMC_CLK_NUM];
57 };
58 
59 /* Return an index in parent table */
60 static inline int plt_reg_to_parent(int reg)
61 {
62 	switch (reg & PMC_MASK_CLK_FREQ) {
63 	default:
64 	case PMC_CLK_FREQ_XTAL:
65 		return 0;
66 	case PMC_CLK_FREQ_PLL:
67 		return 1;
68 	}
69 }
70 
71 /* Return clk index of parent */
72 static inline int plt_parent_to_reg(int index)
73 {
74 	switch (index) {
75 	default:
76 	case 0:
77 		return PMC_CLK_FREQ_XTAL;
78 	case 1:
79 		return PMC_CLK_FREQ_PLL;
80 	}
81 }
82 
83 /* Abstract status in simpler enabled/disabled value */
84 static inline int plt_reg_to_enabled(int reg)
85 {
86 	switch (reg & PMC_MASK_CLK_CTL) {
87 	case PMC_CLK_CTL_GATED_ON_D3:
88 	case PMC_CLK_CTL_FORCE_ON:
89 		return 1;	/* enabled */
90 	case PMC_CLK_CTL_FORCE_OFF:
91 	case PMC_CLK_CTL_RESERVED:
92 	default:
93 		return 0;	/* disabled */
94 	}
95 }
96 
97 static void plt_clk_reg_update(struct clk_plt *clk, u32 mask, u32 val)
98 {
99 	u32 tmp;
100 	unsigned long flags;
101 
102 	spin_lock_irqsave(&clk->lock, flags);
103 
104 	tmp = readl(clk->reg);
105 	tmp = (tmp & ~mask) | (val & mask);
106 	writel(tmp, clk->reg);
107 
108 	spin_unlock_irqrestore(&clk->lock, flags);
109 }
110 
111 static int plt_clk_set_parent(struct clk_hw *hw, u8 index)
112 {
113 	struct clk_plt *clk = to_clk_plt(hw);
114 
115 	plt_clk_reg_update(clk, PMC_MASK_CLK_FREQ, plt_parent_to_reg(index));
116 
117 	return 0;
118 }
119 
120 static u8 plt_clk_get_parent(struct clk_hw *hw)
121 {
122 	struct clk_plt *clk = to_clk_plt(hw);
123 	u32 value;
124 
125 	value = readl(clk->reg);
126 
127 	return plt_reg_to_parent(value);
128 }
129 
130 static int plt_clk_enable(struct clk_hw *hw)
131 {
132 	struct clk_plt *clk = to_clk_plt(hw);
133 
134 	plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_ON);
135 
136 	return 0;
137 }
138 
139 static void plt_clk_disable(struct clk_hw *hw)
140 {
141 	struct clk_plt *clk = to_clk_plt(hw);
142 
143 	plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_OFF);
144 }
145 
146 static int plt_clk_is_enabled(struct clk_hw *hw)
147 {
148 	struct clk_plt *clk = to_clk_plt(hw);
149 	u32 value;
150 
151 	value = readl(clk->reg);
152 
153 	return plt_reg_to_enabled(value);
154 }
155 
156 static const struct clk_ops plt_clk_ops = {
157 	.enable = plt_clk_enable,
158 	.disable = plt_clk_disable,
159 	.is_enabled = plt_clk_is_enabled,
160 	.get_parent = plt_clk_get_parent,
161 	.set_parent = plt_clk_set_parent,
162 	.determine_rate = __clk_mux_determine_rate,
163 };
164 
165 static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
166 					void __iomem *base,
167 					const char **parent_names,
168 					int num_parents)
169 {
170 	struct clk_plt *pclk;
171 	struct clk_init_data init;
172 	int ret;
173 
174 	pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
175 	if (!pclk)
176 		return ERR_PTR(-ENOMEM);
177 
178 	init.name =  kasprintf(GFP_KERNEL, "%s_%d", PLT_CLK_NAME_BASE, id);
179 	init.ops = &plt_clk_ops;
180 	init.flags = 0;
181 	init.parent_names = parent_names;
182 	init.num_parents = num_parents;
183 
184 	pclk->hw.init = &init;
185 	pclk->reg = base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
186 	spin_lock_init(&pclk->lock);
187 
188 	ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
189 	if (ret) {
190 		pclk = ERR_PTR(ret);
191 		goto err_free_init;
192 	}
193 
194 	pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
195 	if (!pclk->lookup) {
196 		pclk = ERR_PTR(-ENOMEM);
197 		goto err_free_init;
198 	}
199 
200 err_free_init:
201 	kfree(init.name);
202 	return pclk;
203 }
204 
205 static void plt_clk_unregister(struct clk_plt *pclk)
206 {
207 	clkdev_drop(pclk->lookup);
208 }
209 
210 static struct clk_plt_fixed *plt_clk_register_fixed_rate(struct platform_device *pdev,
211 						 const char *name,
212 						 const char *parent_name,
213 						 unsigned long fixed_rate)
214 {
215 	struct clk_plt_fixed *pclk;
216 
217 	pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
218 	if (!pclk)
219 		return ERR_PTR(-ENOMEM);
220 
221 	pclk->clk = clk_hw_register_fixed_rate(&pdev->dev, name, parent_name,
222 					       0, fixed_rate);
223 	if (IS_ERR(pclk->clk))
224 		return ERR_CAST(pclk->clk);
225 
226 	pclk->lookup = clkdev_hw_create(pclk->clk, name, NULL);
227 	if (!pclk->lookup) {
228 		clk_hw_unregister_fixed_rate(pclk->clk);
229 		return ERR_PTR(-ENOMEM);
230 	}
231 
232 	return pclk;
233 }
234 
235 static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk)
236 {
237 	clkdev_drop(pclk->lookup);
238 	clk_hw_unregister_fixed_rate(pclk->clk);
239 }
240 
241 static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
242 					       unsigned int i)
243 {
244 	while (i--)
245 		plt_clk_unregister_fixed_rate(data->parents[i]);
246 }
247 
248 static void plt_clk_free_parent_names_loop(const char **parent_names,
249 					   unsigned int i)
250 {
251 	while (i--)
252 		kfree_const(parent_names[i]);
253 	kfree(parent_names);
254 }
255 
256 static void plt_clk_unregister_loop(struct clk_plt_data *data,
257 				    unsigned int i)
258 {
259 	while (i--)
260 		plt_clk_unregister(data->clks[i]);
261 }
262 
263 static const char **plt_clk_register_parents(struct platform_device *pdev,
264 					     struct clk_plt_data *data,
265 					     const struct pmc_clk *clks)
266 {
267 	const char **parent_names;
268 	unsigned int i;
269 	int err;
270 	int nparents = 0;
271 
272 	data->nparents = 0;
273 	while (clks[nparents].name)
274 		nparents++;
275 
276 	data->parents = devm_kcalloc(&pdev->dev, nparents,
277 				     sizeof(*data->parents), GFP_KERNEL);
278 	if (!data->parents)
279 		return ERR_PTR(-ENOMEM);
280 
281 	parent_names = kcalloc(nparents, sizeof(*parent_names),
282 			       GFP_KERNEL);
283 	if (!parent_names)
284 		return ERR_PTR(-ENOMEM);
285 
286 	for (i = 0; i < nparents; i++) {
287 		data->parents[i] =
288 			plt_clk_register_fixed_rate(pdev, clks[i].name,
289 						    clks[i].parent_name,
290 						    clks[i].freq);
291 		if (IS_ERR(data->parents[i])) {
292 			err = PTR_ERR(data->parents[i]);
293 			goto err_unreg;
294 		}
295 		parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
296 	}
297 
298 	data->nparents = nparents;
299 	return parent_names;
300 
301 err_unreg:
302 	plt_clk_unregister_fixed_rate_loop(data, i);
303 	plt_clk_free_parent_names_loop(parent_names, i);
304 	return ERR_PTR(err);
305 }
306 
307 static void plt_clk_unregister_parents(struct clk_plt_data *data)
308 {
309 	plt_clk_unregister_fixed_rate_loop(data, data->nparents);
310 }
311 
312 static int plt_clk_probe(struct platform_device *pdev)
313 {
314 	const struct pmc_clk_data *pmc_data;
315 	const char **parent_names;
316 	struct clk_plt_data *data;
317 	unsigned int i;
318 	int err;
319 
320 	pmc_data = dev_get_platdata(&pdev->dev);
321 	if (!pmc_data || !pmc_data->clks)
322 		return -EINVAL;
323 
324 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
325 	if (!data)
326 		return -ENOMEM;
327 
328 	parent_names = plt_clk_register_parents(pdev, data, pmc_data->clks);
329 	if (IS_ERR(parent_names))
330 		return PTR_ERR(parent_names);
331 
332 	for (i = 0; i < PMC_CLK_NUM; i++) {
333 		data->clks[i] = plt_clk_register(pdev, i, pmc_data->base,
334 						 parent_names, data->nparents);
335 		if (IS_ERR(data->clks[i])) {
336 			err = PTR_ERR(data->clks[i]);
337 			goto err_unreg_clk_plt;
338 		}
339 	}
340 
341 	plt_clk_free_parent_names_loop(parent_names, data->nparents);
342 
343 	platform_set_drvdata(pdev, data);
344 	return 0;
345 
346 err_unreg_clk_plt:
347 	plt_clk_unregister_loop(data, i);
348 	plt_clk_unregister_parents(data);
349 	plt_clk_free_parent_names_loop(parent_names, data->nparents);
350 	return err;
351 }
352 
353 static int plt_clk_remove(struct platform_device *pdev)
354 {
355 	struct clk_plt_data *data;
356 
357 	data = platform_get_drvdata(pdev);
358 
359 	plt_clk_unregister_loop(data, PMC_CLK_NUM);
360 	plt_clk_unregister_parents(data);
361 	return 0;
362 }
363 
364 static struct platform_driver plt_clk_driver = {
365 	.driver = {
366 		.name = "clk-pmc-atom",
367 	},
368 	.probe = plt_clk_probe,
369 	.remove = plt_clk_remove,
370 };
371 builtin_platform_driver(plt_clk_driver);
372